Osteoporosis is a growing public health problem as a consequence of its associated fractures, especially of the proximal femur. Although the focus in the past has been on the problem of osteoporosis in white women, there is increasing recognition that osteoporotic fractures also pose a threat to other populations. In 1995, for example, 6.5% of the total cost of osteoporotic fractures in this country, $901 million, was due to fractures in nonwhites. Their lower cost is a consequence of lower fracture risk, particularly among African-Americans. However, it remains unclear whether this is due to greater bone mass or to other factors. The goal of this proposal is to assess bone mineral density in African-American residents of the community and compare with the results for white and Somali residents after correcting for differrences in body composition and skeletal size. Our specific aims are as follows: To provide helath education on osteoporosis and on possible preventive measures such as dietary calcium, hormone replacement therapy and exercise; to determine bone mineral density (BMD) levels among the African-American men and women residing in Olmsted County and to compare these with the distribution of bone density aming white residents of the County and among residents who migrated from Africa (Somalia) more recently; to examine the association between bone density and body composition, life-style (e.g., smoking) and, for the women, reproductive factors (e.g., parity, age at menopause); on the basis of these data, to recommend strategies to prevent osteoporosis among African-Americans; and in follow-up at two-year intervals, to inquire what lifestyle changes have been made and to assess changes in BMD of the hip and spine.